IFN-beta is an effective agent in the treatment of chronic active hepatitis B and C, and hairy cell leukemia. In addition, IFN-beta is currently in clinical trials examining its effect on a broad range of viral infections and neoplasms, and has recently shown great promise in the management of patients with multiple sclerosis. Critical to understanding the mechanism of action of IFN-beta and its clinical impact is an understanding of its gene regulation. The aim of the present proposal is to identify the mechanism of transcriptional activation by the IFN-beta enhancer. Regulatory factors, including NF-kappa/B, ATF-2, HMG I(Y), and IRF-1 that appear to play essential roles in transcriptional stimulation of the IFN-beta gene have been previously identified and characterized. The proposal addresses the nature of the interaction of transcriptional activators with the basal transcriptional machinery by affinity chromatography of the basal factors on immobilized enhancer DNA- transcriptional activator complexes. Retained basal factors will be detected by in vitro transcription assays, which should allow determination of which basal factors are recruited by the IFN-beta enhancer. Subsequent analogous studies in which the enhancer is selectively mutated to systematically abolish binding of the various transcriptional activators to the enhancer should allow the determination of whether the transcriptional activators differ in their recruitment of basal factors. These studies are a significant advance beyond previous work in that they offer the possibility of determining whether synergy in transcriptional activation is due to recruitment of a single or multiple basal transcription factors. In other words, do all of the transcriptional activators recruit a single basal factor, such as TFIIB, or do they each recruit a separate factor, such as TFIIB by one, TFIID by another, TFIIE by another?